Esmolol is best described as what type of drug?

• A. Esmolol is a short-acting beta-1 selective blocker
• B. Esmolol is a non-selective beta-blocker
• C. Esmolol is a calcium channel blocker
• D. Esmolol is an alpha-adrenergic agonist

Answer: (A)

Esmolol is a short-acting beta-1 selective blocker. In the heart, beta-1 receptors increase heart rate, contractility, and AV nodal conduction. Blocking these receptors lowers heart rate and slows conduction, which is why esmolol is used to control tachyarrhythmias and tachycardia during procedures. What makes esmolol stand out is its ultra-short duration: it is rapidly metabolized by plasma esterases, giving a very short half-life (about 9 minutes). This allows precise titration and quick reversal if blood pressure or heart rate drop too much when the drug infusion is stopped. It’s given IV and is especially useful when you need rapid, controllable heart-rate reduction. It’s not a non-selective beta-blocker (which would affect beta-2 receptors and risk bronchospasm), not a calcium channel blocker, and not an alpha-adrenergic agonist.